Long-term changes in the number of birds of the Barguzin Range (North-Eastern Baikal Region)
A. A. Ananin1,2
1Federal State Establishment “United Administration of Barguzinsky State Nature Biosphere Reserve and Zabaikalsky National Park” (FSE “Zapovednoe Podlemorye”), Ust-Barguzin, Russia
2Institute of General and Experimental Biology Siberian Branch of the RAS, Ulan-Ude, Russia
Keywords: Baikal, population dynamics, long-term monitoring, bird population, number counts
Abstract
А 36-year study of bird number dynamics (1984-2020) on permanent accounting routes from the coast of Lake Baikal to the Barguzin Range highlands (460-1700 m s. l.) were performed. A steady decrease in the total abundance of background bird species after 1997-1998 was revealed. The resulting long-term series (as the example of model groups of birds) made it possible to identify the responses of the biota on climatic changes in the Lake Baikal region. Periods of high and low numbers in bird`s populations are probably associated with the passage of a wet and arid phases of a climatic cycle. In 8 background species (16.0 %), positive trends of long-term changes in abundance were revealed, and in 18 species (36.0 %), a steady decrease in abundance was established. Negative trends in population changes in distant migrants prevail over growth trends (11 species against 3 with positive trends). Some mechanisms of the formation of the local bird`s population are disclosed, including using the redistribution of the nesting species density between the river valleys and habitats at the high-altitude profile. Current long-term climate change in the region has a positive impact on changes in the abundance of background bird species in the highlands compared to the underlying mountain forest belt.
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